Process for converting hydrocarbon oils



`1` A y f r Feb., 9p M342. Fa. T. POLLGCK PROCESS FOR CGNVERTING HYDROGARBON OILS Original Filed May l2. 1920 Patented Feb. v9, 1932 UNITED STATES ROBERT T. POLLOCK, 0F NEW YORK, N. Y.,

PATENT oFFlcE ASSIGNOR TOv UNIVERSAL OIL PRODUCTS PROCESS FOR GONVERTING HYDROCARBON OILS ontinuaton of applicationy Serial No. 380,746, led May 12, 1920. This application led September 28,

1928. Serial No. 309,108.

This invention relates to improvements in a process and apparatus for converting hydrocarbon oils and refers more particularly to a process by Which a greater quantity of the low boiling point hydrocarbons may be recovered in the initial cracking of the oil.

rlhis application is a continuation of my application Serial No. 380,746, filed May 12, 1920.

Among the salient objects are to provide a process in which the raw oil, besides acting as a cooling agent to assist in condensing the higher boiling point cuts from the oil vapors, is at the same time, preheated by the vapors; to provide a process in which this condensation and preheating takes place Without the oil vapors coming in contacting relation with the raw oil, thereby obviating the objectionable feature of havingasubstantial portion of the low boiling point vapors extracted With the higher boiling point fractions to combine with the reflux condensate; to provide a process in which the reflux may be combined with the raw oil subsequent to the dephlegmation' of the vapors and one in which the relative proportions ofthe mixture may be positively controlled; to provide an improved apparatus for the carrying out offthis process and in general to provide a process and apparatus of the character referred to.

The single ligure in the drawing shows a diagrammatic elevational view of the apparatus.

Referring in detail to the drawing, the raw oil is charged from any convenient I source to the pump 1 by the inlet pipe 2.

-l Ct From the pump it is directed through the line 3, which is controlled by a valve 4 to a coil 5' mounted within the partial condenser ti. This partial condenser comprises a casing member in which are circulated the oil va-l pors. The raw oil, after being preheated in this partial condenser is drawn off through the line 8, which is controlled by valves 9 and 10. A by-pass 11, controlled by a valve 12, furnishes a means for by-passing the raw oil around the partial condenser. The raw oil is supplied to a mixing tank 13, which is connected to the reflux collecting tank 14 by a fluid line 15, controlled by a valve 16 and a gas connecting line 17. The reflux collecting tank is supplied with reflux through the drawo pipe 18, which is controlled by a valve 19. This reflux is taken from the bottom' of the dephlegmator 20. By-pass lines 21 and 22 controlled by valves 23 and 24 respectively, furnish means of by-passing the redux and the raw oil around the collecting tank 14 and mixing tank 13. When these tanks are cut out, the reflux combines with the raw oil directly. A secondary connecting line 25, controlled by valve 26, diverts the reflux from the drawol line 18 to the tank 14. A similar line 27, controlled byY valve 28 directs the raw oil with its reflux content to the charging line 29, controlled by a valve 30.

The oil charge is then supplied to the heating tubes 31, which are mounted above a furnace 32, the latter being preferably heated by gas burners 33. The heated oil, after being subjected to a cracking temperature, passes into the vapor chamber 34 through the connecting line 35. The oil vapors released in the vapor chambers are directed to the dephlegmator through the riser 36 and connecting line 37. A valve 38 is interposed in y this line. The oil vapors which are introduced to the bottom of the dephlegmator rise through the successive stages in which they are dephlegmated by being caused to pass through shallow pools of reiux condensate, the level of which is maintained by `suitable standpipes 40. After passing up through the successive stages through the risers 39, the uncondensed vapors pass off through the line 41 which is regulated by valve 42 and are circulated about the coil pipe 5, which is mounted in the partial condenser. The interchanging of heat Which takes place inthe partial condenser causes an additional portion of the higher boiling point hydrocarbons to condense from the vapors, and pass back into the dephlegmator through the return line 48 regulated by valve 44. TheV uncondensed vapors from this partial condenser pass 0H through the gooseneck 45, which has interposed therein a valve 46. These vapors are condensed in the spiral tube 47 which is mounted in a water condenser 48 and pass off as distillate through the drawoff line 49, controlled by valve 50 to a receiver in the tail house (not shown) A residuum drawoff line 51 controlled by valve 52 is tapped into the va or chamber for drawinor o the heavier oils with the preci itated carbon.

The operation o the process is as follows: The raw oil is introduced to the partial condenser and preheated therein by having the oil vapors circulated around a coil pipe through which the raw oil iows. After berectly to the raw oil through the by-pass lines. The uncondensed vapors on the other hand, rise through the dephlegmator and circulate about the coil containing the raw oil in the partial condenser where a portion of the vapors are condensed and returned to combine with the reiiux in the dephlegmator. The

, vapors not condensed pass over to be collected as distillate after being condensed in the water condenser. In this manner, it is possible to preheat the raw oil and at the' same time, take advantage of the cooling and condensing properties of the raw oil by circulating the .vapors about a coil containing the incoming oil charge. At the same time,

this process obviates the objection of inter-I mingling the raw oil and the vapors -as this intermingling extracts a substantial portion .of the lighter oil fractions from the vapors during dephlegmation.

The following is anillustrative run of the process: Charging gas oilfrom the mid-conproduce lighter fractions having an end point of approximately 450 F After passing through the'dephlegmator, 8% to 9% of said vapors are recovered as distillate in the receiver, while two or three per cent by weight combine with the reflux and are returned to be retreated, after being mixed with the raw oil. By interchanging the heat of the vapors to the raw oil'and taking advantage of the coolingand condensing properties of the oil by contacting the vapors and the oil by radiation, the efficiency of the process 1s greatly increased, due to the fact that the incoming oill which has a very appreciable aiinity for the lighter fractions of the oil, is not permitted to contact the vapors in the manner that it may take these lighter fractions therefrom.

Having thus described my invention, what I claim is:

l. A continuous process for cracking hydrocarbon oil, consisting in raising the oil to a cracking temperature in a single pass through a heating zone, in delivering the heated oil to an enlarged reaction chamber," wherein substantial conversion occurs, in subjecting the vapors to reflux condensation by causing them to initially pass through successive pools of reflux condensate free from other constituents, in then passing the vapors in heat interchange relation with incoming charging oil, to preheat such incoming charging oil.and separate from the vapors insuiiciently cracked fractions, in subjecting the uncondensed vapors to nal condensation, in uniting the preheated charging oil with regulated proportionsof reflux condensate separated from the vapors ina mixing chamber, wherein a reserve supply of heated material for the process is maintained and in continuously supplying the comminled reiiux condensate and preheated chargmg; oil from said mixing tank to said heating zone, and in maintaining a superatmospheric pressure o n the oil undergoing conversion in the process.

2. A process for cracking hydrocarbon oil, consisting in raising the oil to a cracking `temperature in a single pass through a heating zone, in delivering the heated oil to an enlarged reaction chamber, wherein substantial conversion occurs and from which no unvaporized oil is permitted to return to said heating zone, in subjecting vapors evolved from the oil to reflux condensation by causing` the same to initially pass through successive pools of reiux condensate free from other constituents, in thereafter causing the vapors to flow in heat interchange relation with incoming charging oil for the process, to preheat such charging oil and condense insuiiiciently cracked fractions of the vapors,

in uniting the insuiciently cracked fractions of the vapors condensed by passage in heat interchange relation with the charging oit with the reflux condensate in the last pool through which the vapors pass, in subJecting the uncondensed vapors to final condensation, in uniting 'the preheated charging oil with predetermined proportions of reiux condensate in a mixing tank, wherein a. heated supply of commngled charging oil and reflux condensate is maintained for the process, in continuously supplying such corniningled oils from said tank to said heating zone, and in maintaining asuperatmospheric pressure on the oil` undergoing converslon in the process.

1in testimony whereof I aiix my signature.

RBERT THOS. POLLOCK. 

